Immobilizing Different Carbon Sources in Alginate Beads for Melanoidins Removal from Yeast Effluents

Presently work describes a new method for melanoidins removal encountered in yeast industry effluents. Three different kinds of carbon sources were inmobilized in alginate beads and include rubber tire pyrolysis, activated carbon and multiwalled nanotubes. The yeast effluent was obtained through aerobic fermentation with 40 g/L of molasses. The effluent was separated through filtration. The alginate beads consisted in 3 g of alginate and 4 g of the carbon sources, which were dissolved in one liter of distilled water. The last was added drop by drop into a solution of CaCl 2 (15 g/L). The alginate beads were used in different proportions (w/v) in the effluent (1:6, 1:3.5, 1:2.6 and 1:1). The melanoidins amount adsorbed was determined through a spectrophotometer UV vis (600 nm). At 1:1, the concentration of melanoidins at the equilibrium (qe) for rubber pyrolysis was 3.5 mg/g, for the activated carbon was 5.0 mg/g, for multiwalled nanotubes qe was 5.3 mg/g and when the alginate beads probed alone qe was only 1.5 mg/g. In order to predict the adsorption capacity in a continuous stirred tank we assessed the saturation constant (Ks) in the batch treatments. The continuous fermenter was simulated from 0.01 to 1.0 h -1 dilution rates. At the lowest proportion (w/v) 1:6 the maximum sorbtion capacity was at 0.427 g/L.h obtained with the rubber pyrolysis at 0.26 h -1 . When we used a proportions (w/v) of 1:3.5, 1:2.6 and 1:1, the maximum adsorption capacity were 0.77, 1.04 and 1.13 g/L.h, respectively and these values were obtained with multiwalled nanotubes.